Ultrasonic Measurement of Phase and Group Velocity Using Continuous Wave Transmission Techniques.

Abstract

AMMRCCTR-73-2(*composite materials, nondestructive testing), (*halocarbon plastics, ultrasonic radiation), test methods, test equipment, propagation, velocity, attenuationphase, velocity, group velocity, tetrafluoroethylene resins, *ultrasonic testsPhase and group velocities V and U, respectively, were measured in the 100:1 frequency range 50 kHz to 5 MHz using longitudinal and shear ultra-sonic continuous waves in teflon and in a dispersive three-dimensional reinforced composite. A new transmission approach was developed which utilized broadband transducers and a pair of wedges to obtain V BY A DIFFERENTIAL PATH, FIXED FREQUENCY TECHNIQUE, AND TO OBTAIN U by fixed-path, differential frequency technique. The path or frequency was incremented to fit additional whole wavelengths in the path, as indicated by 2 pi phase shifts in a Lissajous pattern. Cross-checks between U AND V confirmed the validity of the approach at least for the two materials investigated. (Author-PL)

Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1973
Accession Number
AD0756385

Entities

People

  • Emmanuel P. Papadakis
  • Lawrence C. Lynnworth
  • Warren R. Rea

Tags

DTIC Thesaurus Topics

  • Broadband Transducers
  • Composite Materials
  • Continuous Waves
  • Frequency
  • Group Velocity
  • Halocarbon Plastics
  • Materials
  • Materials Testing
  • Nondestructive Testing
  • Plastics
  • Resins
  • Test Equipment
  • Test Methods
  • Tetrafluoroethylene Resins
  • Ultrasonic Radiation
  • Wave Propagation

Readers

  • Control Systems Engineering.
  • Optical Physics and Photonics.
  • Structural Health Monitoring of Composite Structures.